Unlike most granular synths, Grain Science was designed to behave like a normal synth. You've got all of the parameters you're used to, and it can be used as one of the best wavetable synths on any platform. Additionally there are many interesting assignable effects. The "science" comes in the form of elaborate modulation methods that go beyond typical ADSRs. If you want to get into the granular stuff you can sample, import and record your own sounds to tweak and retweak. There is full MIDI support (including Virtual), an excellent "MIDI Learn" implementation. Watch the full review here.

Development continues with a recent update that added an Animoog style ribbon controller, as well as an improved Arpeggiator and more effects.

What GrainBender lacks in Granular, it makes up for in the bending department. A wide array of modulation options provides many sonic possibilities; made all the more evolving by the most intuitive automation on any platform. If you see it, you can bend it and make it dance however you like, whenever you like. The inclusion of well documented MIDI IN/OUT make it useful as well when working with other MIDI hardware and software, providing the opportunity to utilize the bending automation in other gear or DAWs. Watch the full review here.

With the fragmentation of Music Apps between AudioCopy/Paste and PasteBoard, Hokusai is your bridge to getting them playing nicely with one another. Supporting both formats, seamlessly, it is a godsend. Almost as a bonus it is also a full-on audio editor, with fluid controls. Working with samples is a breeze once you get used to it. See it in action in my BeatMaker 2 Review

iDensity is an interesting take on granular synthesis, in a straight-forward package. All of your controls are presented on one page with a series of sliders to control things like grain size and randomization. I found it to be pretty fun for drones, but without any MIDI or even an on-screen keyboard, drones are pretty much what you'll be limited to. If you want musicality in your granularity you should consider SampleWiz or Curtis; both of which offer on-screen keyboards and AudioCopy/Paste. Watch a full review here.

Impaktor explores some very unique percussion territory, while being relatively user friendly. Instead of triggering this app with on screen pads, or even an external MIDI controller, it listens to your iDevice's mic for impulses. The intensity and transients that result from you banging on shit in your house can make many different sounds from a single preset.

This is because the entire sound engine is driven by synthesis. Rather than samples, the character of the sounds you create near the mic are fed through a synthesis engine; to make new original tones. The engine is quite deep too, from the makers of Sunrizer. If you're not up for diving into the dual-synth engine here, there are a 92 factory presets that cover Electronic, Ethnic, Imaginary and Industrial percussion. I'm deeply impressed with some of their pseudo-acoustic presets.

There is also a great six track recorder, which can have varying loop lengths. You can even overdub new instruments on top to simulate even more tracks. This is very well designed and easy to work with, including helpful options to clear individual tracks or the whole thing. These tracks or live recordings can be exported via iTunes or Audio Pasteboard.

My only disappointment with Impaktor has been the fixed-screen in portrait mode. This is fine on the iPhone, but on the iPad it can be annoying, especially with the Smart Cover and other stands that work in landscape mode.

3 Oscillators on 3 different Synths! That is a lot of synthesis in one App, when most dedicated synths stop at 2! You get 2 Mono synths with 1 Poly synth and a small drum setup. All of that can be sequenced with what attempts to be a fairly full featured modern sequencer. iSyn Poly was my first review and I had a lot of problems with the sequencer. They have since patched it, but I still find it kind of a pain to work with. It is ambitious though, with automation and the ability to define pattern sizes. Honestly though, with it's MIDI implementation I think you're golden just plugging in your keyboard and playing. The range of sounds you can get with 3 oscillators is already impressive, but with 3 instruments the range in this one app becomes awe inspiring. I especially like the modulation options, and assignable X/Y controller.

While not as complete a package as Korg's iMS-20, it is also not nearly as complicated. Offering a wide assortment of great sounding samples for every genre you can imagine, it is essentially an App version of the Electribe-R Mk2. It is a very intuitive app that anyone should be able to immediatly start playing. For advanced users though; the lack of CoreMIDI clock sync limits it's functionality with other apps. The lack of MIDI Note In is baffling since it is included in the Gorillaz version (Not Reviewed). WIST does provide some extra use, but only when working with multiple devices.

Korg's iMS-20 is an impressive package of synthesis. With a main synth part and 8 sub-synth parts there are a lot of sounds to squeeze out of it, as this goes far beyond the hardware it is emulating. The inclusion of two assignable X/Y pads makes this a great app for performance. You get a Kaossilator with a KaossPad, and the added benefit of being able to assign your own sounds! The only downside in this app is the sequencer, which is archaic. One of my songs, Abrasives and Lubricants, was done entirely in the iMS-20 App.

This little app is very easy to use for making some seriously twisted beats. This looper works like a two-deck DJ app for loops, with 8 DSP effects and filters to lather all over them, or cross-fade between them. Importing is unfortunately limited to iTunes, but export also supports General Pasteboard. Recordings are also limited to whatever you sequence in the 16-step patterns. This is a shame because it is a lot of fun to perform with live. If you've got Loopy then you really want to get this as it is a nice way to build new loops. Read the full review here, and listen to my jam with it on Loopy.

Loopseque sampler-sequencer is a slick and simple way to put together new loops. The sequencer is rounded; really driving home the idea of looping, while also inviting you to try entirely new rhythms beyond throwing the kick on the 1, 5, etc...

You've got 4 sets of patterns to play at any given time, each with their own set of 4 samples. Sliding your finger along the pattern circle will bring up an entirely new pattern. Building up new patterns is quite easy, as they have included the ability to copy pattern data. This is handy for quickly adding variety to your loops!

Recent updates have added a lot of new dimensions to the app, including effects and recording. Loops recorded with Loopseque can be exported via Audio Pasteboard, in addition to iTunes file-sharing and Dropbox. Samples can be imported in much the same way. The new ability to add your own samples, simply by using Audio Pasteboard, adds a lot of potential here. They would like for you to purchase tracks and loops from them for about $1 each, but this is hardly necessary now that you can easily import your own from just about any app.

I did encounter some bugs, including one crash, all related to the recording and recording playback. These weren't terrible, and no data was lost, but I think that is worth mentioning.

meta DJ is unique among iOS DJ apps, both in terms of its modern take on DJing and for its continuing development. This 4-Deck DJ app offers a similar experience to computer DJ software, with features such as cue points and loop-size selection. Several other instruments can be slotted in any of the track slots. The additional instruments can add a lot to a mix, with things like samplers, drum machines and a mini-version of Sound Trends' Looptastic looper. All decks have their own assignable effects units, which can be controlled via an X/Y pad for expressive play. The update cycle has been aggressive on this one; now featuring performance recording as well as Audio Pasteboard import and export. Read the full review here.

This is one of the more disappointing Universal apps. It is packed full of modular goodness with tons of routing options and tweakable settings, but makes no effort to utilize the iPad resolution. To get to even basic functions, like Envelopes, requires digging down through 3-4 pages of menus. This is a very frustrating experience, because you know that you can do some great things with this app, but it will fight you every step along the way.

This fully synthesized grove app has CoreMIDI clock and background audio support to work as a companion app with other apps such as Finger's Bassline. Updates have greatly improved the usability of this app. The synthesis is still kind of weird, offering their own unique control variables, but not with any consistency. Rimshot, for instance, is designed with just Tune, Drive, and Decay. Granted, this is more than you'd get on an 808, but with the many options on other elements this seems disappointing. All effects are global (with no ability to cancel it on individual parts). The interface design is well thought out though, with all parameters controlled by easy-to-use sliders, instead of finicky little knobs.

This is my favorite of the dedicated groove apps. With CoreMIDI clock and a mind boggling assortment of per-part effects and modulations, Molten out Electribes the Electribes. I also really like the easy way it handles patterns and note lengths. The CoreMIDI lets this play with other Apps as well as any external sequencers. With AudioPaste it is also the best option for getting your own sounds into a groove app. Consider getting Hokusai to refine your samples as well as import from PasteBoard sources. Some people prefer FunkBox, but I think this blows it away.

MorphWiz is a unique controller/instrument offering a keyboard interface with an extra-dimension. Instead of your usual note and velocity, you have note and verticality; the height of your press on the key can change the sound. The effect height has can be assigned to everything from wave morphs to rudimentary FM, as well as volume. This is a pretty wild way of playing, and if you're a solid keyboardist with at least one of your hands this can be a great experience. I found the actual synthesis to get boring fairly quickly though, and would have a hard time recommending this to anyone who cannot already play keyboard well. If you like the style though you might want to look at SampleWiz.

127 tracks await in this impressive and easy to use studio app. With easy navigation and note editing, this instantly feels like a professional version of Garageband. It comes packed with lots of interesting sounds, and you can import your own loops, but additional sampled instruments must be purchased via In-App Purchase. This is a little disappointing when many other, similar, apps allow you to make your own instruments. Fortunately they offer an All You Can Eat option for all of the available instruments for an additional $15. This is a great place to put all of your recordings from other apps and work them together into complete songs, with some solid effects to tie it all together.

NanoStudio has been beloved by musicians with iPhones for years, and now it's Universal! This studio app features 6 tracks (upgradable to 16 with a $5 In-App Purchase) for you to fill up with a couple of different types of instruments. The synth/sampler fills in double-duty as your keyboard instrument, with many pages of sound design options. The drum pad instrument makes a fine sampler, with a built in editor. To top it off you have some amazing effects options, with inserts, chains, and sends. This is a great package, but users who want to interact with other apps with virtual MIDI, should consider BeatStudio 2. You can read my full review here, as well as listen to a song I composed entirely in NanoStudio.

4 Oscillators! 4 Envelopes! 4 LFOS! It does all of that with sounds that can go from a very pristine bell, to the darkest pits of industrial metal hell. I cannot understate the amount of modulation allowed. On top of the 4 Envelopes and 4 LFOs, you have 4 additional Mod slots for routing any of those to additional parameters. You can get crazy in there; have your modulators modulating other modulators! With all of this going on there are some issues with navigating through it all, but I think they did a good job of designing it into a logical layout. The CoreMIDI implementation here is as complete as it gets; from MIDI notes and CC, to keeping sync with other apps like Molten.

This Indie nodular modular is best considered a music toy, rather than an instrument. It is a fun toy, allowing you to haphazardly throw notes around the screen to pling and plong endlessly against sound generators. It is a simple interface that anyone can immediately understand, with some options to add a little complexity, such as allowing movement between notes and generators. You could try to use it for directed music, but I think that would be missing the point of what is an exploration of coincidental interactions that happen to be musical. As of version 2.0 there is now an option to run all of the interesting randomness out as MIDI notes, including Virtual MIDI support!

Physynth is an experimental instrument; specifically, experimenting to see if "Experimental" doesn't have to mean random or noise! I think they succeeded, as I was able to get some great sounding and lively beats out what is essential a Physics Looper. The code running the show is based around an engine used for games, and that background makes the physics in play here feel very playful! If you've enjoyed apps like Sound Drop, but wanted more control you should definitely check this out. See a full review here.